Topic Three (1.3): Investigating Ecology

 Introduction

In this topic you will take another look at ecology investigations, which are one of the few core practicals that you might be able to carry out at home! You will also be learning multiple tests to investigate possible correlations between factors (Spearman’s rank correlation coefficient), whether two groups of test subjects differ in a particular variable (Student’s t-test), or whether there is a difference between the observed and expected results involving categoric variables (Chi squared test).

 Reading

Edexcel AS/A Level Biology Student Book 2 pages 37 to 47 and 310 to 312

Edexcel International AS/A Level Biology Lab Book pages 56 to 61

 Read and Make Notes

Read pages 37 to 40, making appropriate notes and completing the ‘in-text’ questions.

Tasks

Complete the following:

• Complete worked example 5 to calculate species diversity on page 313.

Practical Knowledge

• Read page 57 in the Lab Book, and the Core Practical – Ecology sheet which is designed to help home schooling students conduct their own experiment.

READ – Core Practical – Ecology Download READ – Core Practical – Ecology

USE – Field Plants Key Download USE – Field Plants Key

• Carry out the practical described to investigate somewhere close to your home. Use your results and investigation to fill in the results and conclusions on pages 58 to 61.
• Check your answers in the back of the book and using the model answers on Canvas.

OBSERVE – Practical 11 Model Answers Download OBSERVE – Practical 11 Model Answers

 Read and Make Notes

Read pages 41 to 47 in the textbook. Pay close attention to the worked examples, follow them through yourself and check yourself at every stage.

Tasks

Complete the following:

• Read pages 310 to 312 and worked example 4.
• Complete questions 1 to 2 on page 48.

 Consolidate

Now consolidate your understanding by working through these additional resources:

REVIEW – Statistics Section of the AQA Handbook (AQA) Download REVIEW – Statistics Section of the AQA Handbook (AQA)

– Although this is a different syllabus, it covers a lot of practical skills very clearly.

READ - Chi-Squared Test for Association (Bio Factsheet) Download READ - Chi-Squared Test for Association (Bio Factsheet)

READ - The Paired t-Test (Bio Factsheet) Download READ - The Paired t-Test (Bio Factsheet)

READ - Which Stats Test Should I Use? (Bio Factsheet) Download READ - Which Stats Test Should I Use? (Bio Factsheet)

READ - Answering Exam Questions on Statistics (Bio Factsheet) Download READ - Answering Exam Questions on Statistics (Bio Factsheet)

 Top Tips

Make sure that you understand the following key points:

• The most useful thing to do when it comes to statistics is lots of practise! Watch videos about them, work along with the worked examples in the textbooks, and have a go at the questions.
• It’s important to know when to use the different statistical tests. The following points might help:
  • Spearman’s Rank: Is the number of daisies changing as you get further from the tree?
  • Student’s T-test: Is the mean flower size of daisies different in these two fields?
  • Chi Squared: Are you more likely to find daisies near dandelions or not? (but note that Chi squared is also very commonly used in genetics to investigate the 3:1 ratio).

 Key Terms

Check that you know all of the terms in the Subject Vocabulary boxes on pages 40 and 47 and add any you don’t know to your glossary.

 Quiz

Complete Quiz 01: Photosynthesis and Ecology. If you score less than 90%, try again.

 Assignment

When you have completed all the activities and are fully prepared and feel confident with the material, you should complete Assignment One and submit it to your tutor via Canvas for marking and feedback.